Non-linear materials and related devices

Abstract

A non-linear optical device comprising a non-linear element made of a plasmonic material with a periodic structure having a period smaller than the wavelength of a non-linear process intrinsic to the plasmonic material. The plasmonic material is implemented as a gold film which is structured with a periodic array of asymmetric split ring slits. The metamaterial framework of the plasmonic material itself is used as the source of a strong and fast non-linearity. The cubic non-linear response is resonantly enhanced through the effect of the metamaterial structuring by more than two orders of magnitude and its sign and magnitude can be controlled by varying the metamaterial pattern.

Description

BACKGROUND OF THE INVENTION[0001]This invention relates to non-linear materials and non-linear devices incorporating such materials.[0002]Conventional non-linear media are unlikely to be able to provide the speed and strength of non-linear effect that are needed by next generation data processing circuits and all-optical switches. To overcome this bottleneck, metamaterials are being researched. A non-linear metamaterial is an artificial medium structured on a size scale smaller than the wavelength of the external stimulus which induces the non-linear process, wherein the sub-wavelength structure serves to enhance the non-linear process. A layer of a conventional non-linear material such as semiconductor or carbon nanotubes has been combined with a layer of metal which support surface plasmon polaritons and has been meta-structured to enhance non-linearities in the non-linear material.[0003]References 1 and 2 disclose a periodically structured two-dimensional grid-like structure, ref...

AI Technical Summary

Benefits of technology

[0006]We have demonstrated that the metal of the metamaterial framework itself can be used as the source of an even faster non-linearity than has ever been achieved with a metal metamaterial on a semiconductor or CNT. In particular, the cubic non-linear response of the non-linearity in the metal can be resonantly enhanced through metamaterial structuring by more than two orders of magnitude and its sign and magnitude can be controlled by varying the metamaterial pattern. This gigantic engineered non-linearity in structured metal, which is at least one order of magnitude faster than the fastest non-linearities in metamaterials reported so far [1, 4], can be engaged to control light with light on the femtosecond time scale at an average power level of only a few milliwatts.

[0011]The flexibility of the metastructuring of the metal allows a resonantly enhanced, ultrafast non-linear optical response to be achieved at any desired wavelength across the visible to near-infrared wavelength range. Compared with prior art hybrid metamaterials, the proposed materials and related devices should be simpler and hence cheaper to produce. This is because the proposed medium can be fabricated solely of one material, i.e. one metal, in particular one pure metal. By contrast, prior art hybrid structures impose additional constraints both physical and practical, because of the need to combine a metal with a semiconductor or other non-linear medium, and to structure this hybrid structure through suitable etching or other processing. Factors such as chemical compatibility and mutual adhesion must be considered as well as choosing an etching process for structuring the metal which is compatible with the semiconductor or other non-linear medium.

Problems solved by technology

Conventional non-linear media are unlikely to be able to provide the speed and strength of non-linear effect that are needed by next generation data processing circuits and all-optical switches.

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